Possibly wankabrams didn't sound as funny. Nor would wanksherman or wankM3. (also, other tanks names, though they would convey the excessive mass and girth of the loathed SUVs, don't stand as a single word. Sherman tanks, Abrams tanks, et al, all need "tank" in their common usage, but Panzers...are just Panzers.)
Afterthought: wanksherman, when heard, sounds a bit like a male resident of someplace called Wankshire. Which I would imagine is a place that could only exist in a comedic novel or sketch.
Since there is actually a town in Newfoundland named Dildo, I cannot completely rule out the possible existence of a Wankshire.
How Wankshiremen might feel about ambulato-mechanical onanists is an open question.